Titanium alloys can experience a cooling-induced phase transformation from a body-centred cubic phase into a hexagonal close-packed phase which occurs in 12 crystallographically equivalent variants. Among them, variant selection II, 60°/$〈1\overline{2}10〉$, is very close to the orientation of $\left\{10\overline{1}1\right\}〈1\overline{2}10〉$ twins (57.42°/$〈1\overline{2}10〉$). We propose that the cyclic thermal loading during additive manufacturing introduces large thermal stresses at high temperature, enabling grain reorientation that transforms the 60°/$〈1\overline{2}10〉$ variant boundaries into the more energetically stable 57.42°/$〈1\overline{2}10〉$ twin boundaries. This transformation twinning phenomenon follows a strain accommodation mechanism and the resulting boundary structure benefits the mechanical properties and thermal stability of titanium alloys.

钛合金会经历冷却诱导的相变，该相变由体心立方相转变为六方密堆积相，这种相变出现在12个晶体学等效的变体中。其中，变体选择II，60°/$〈\mathrm{1个}\overline{2}10〉$，非常接近 $\left\{10\overline{\mathrm{1个}}\mathrm{1个}\right\}〈\mathrm{1个}\overline{2}10〉$ 双胞胎（57.42°/$〈\mathrm{1个}\overline{2}10〉$）。我们建议，增材制造过程中的循环热负荷会在高温下引入较大的热应力，从而使晶粒重新定向，从而改变60°/$〈\mathrm{1个}\overline{2}10〉$ 变体边界进入更加稳定的57.42°/$〈\mathrm{1个}\overline{2}10〉$双重边界。这种转变孪生现象遵循应变适应机制，并且所产生的边界结构有利于钛合金的机械性能和热稳定性。